linux-kernel - Re: [PATCH V1 2/2] ufs: ufs-qcom: Disable AHIT before SQ tail update to prevent race in MCQ mode

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Message-ID: <e3fa13724a08bfaa764d57a3d223d201cd4d30c0.camel@mediatek.com>
Date: Mon, 20 Oct 2025 06:53:06 +0000
From: Peter Wang (王信友) <peter.wang@...iatek.com>
To: "palash.kambar@....qualcomm.com" <palash.kambar@....qualcomm.com>,
	"bvanassche@....org" <bvanassche@....org>
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Subject: Re: [PATCH V1 2/2] ufs: ufs-qcom: Disable AHIT before SQ tail update
 to prevent race in MCQ mode

On Sat, 2025-10-18 at 12:14 +0530, Palash Kambar wrote:
> Thanks for the feedback, Bart. However, I believe setting the runtime
> suspend delay to 5ms
>  might be overly aggressive for the system and may have below side
> effects:
> 
> 1. Short autosuspend timeouts can cause the UFS device to enter low-
> power states even
> during brief idle periods. This results in resume latency,
> introducing delays when the
> device needs to wake up for subsequent operations.
> 2. Frequent suspend and resume cycles may disrupt data flow,
> particularly in workloads
> with bursty or intermittent I/O, leading to performance degradation.
> 3. When the autosuspend timer is overly aggressive, the UFS device
> may repeatedly
> transition between active and low-power states. These transitions
> themselves consume power,
> and if they occur too often, they can offset or even negate the
> intended power savings.
> 
> Please let me know your thoughts on this.
> 
> Regards,
> 
> 
> Palash K
> 

Hi Palash,

Maybe disabling AH8 and enabling both UFSHCD_CAP_CLK_SCALING
and UFSHCD_CAP_HIBERN8_WITH_CLK_GATING is sufficient?

Thanks
Peter

>